Quantum Character

“ Nonlocal character of quantum theory ”

There has been considerable discussion of the claim by Stapp [1] that quantum theory is incompatible with locality. In this note I analyze the meaning of some of the statements used in this discussion.

Nonlocal character of quantum theory?

In a recent article under the above title (but without the question mark) Henry Stapp presented arguments which lead him to conclude that under suitable conditions “the truth of a statement that refers only to phenomena confined to an earlier time” must “depend on which measurement an experimenter freely chooses to perform at a later time.” I point out that the reasoning leading to this conclus...

The Non-mechanistic Character of Quantum Computation

The higher than classical efficiency exhibited by some quantum algorithms is here ascribed to their non-mechanistic character, which becomes evident by joining the notions of entanglement and quantum measurement. Measurement analogically sets a (partial) constraint on the output of the computation of a hard-to-reverse function. This constraint goes back in time along the reversible computation ...

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The question raised by Shimony and Stein is examined and used to explain in more detail a key point of my proof that any theory that conforms to certain general ideas of orthodox relativistic quantum field theory must permit transfers of information over spacelike intervals. It is also explained why this result is not a problem for relativistic quantum theory, but, on the contrary, opens the do...

On the Ising character of the quantum-phasetransition in LiHoF4